1. Field of the Invention
The present invention relates to a vehicle diagnosing apparatus for diagnosing a vehicle such as a motor vehicle. The diagnosing apparatus is connected to an electronic control unit to be mounted on the vehicle and incorporates or receives data, via the electronic control unit, from various sensors which are mounted on the vehicle.
2. Description of the Related Art
As a method of inspecting a logic of a diagnosing program of this kind of diagnosing apparatus, there is known the following. Namely, a vehicle whose diagnosing has already been finished is diagnosed by means of a diagnosing apparatus which performs diagnosing according to a diagnosing program for an object to be inspected. It is thus checked whether each of the diagnosing items is diagnosed in a predetermined order, and whether the result that is the same as the known result can be obtained. An inspection is thereby made whether the logic of the diagnosing program is normal or not.
In the diagnosing program, the succeeding processing is defined depending on the judging results and, therefore, varies from result to result. Accordingly, in order to inspect the logic of all portions of the diagnosing program in the conventional method, it is necessary to prepare several vehicles so that all kinds of judging results can be obtained for each of the judging items and then subject each of the vehicles to actual diagnosing. In case the judging items are large in number, a large number of vehicles must be diagnosed. This, however, requires a long time in inspection and is practically difficult. Especially, since most of the vehicles are normal, there is little or no chance of checking the processing of a diagnosing apparatus after it has been judged to be "abnormal." It is thus difficult to inspect to see whether the logic of this portion is normal or not.
If a special electronic control apparatus for inspection is prepared so that all kinds of judging results can be obtained, it will be possible to perform a complete inspection in a short period of time. However, this kind of apparatus prepared exclusively for such an inspection is complicated in construction. Further, the apparatus becomes needless once the inspection is finished. It is therefore not advisable to use this kind of specially prepared apparatus.
The present invention has an object of providing a vehicle diagnosing apparatus in which it is not necessary to prepare a vehicle or an electronic control apparatus as an apparatus to be diagnosed when the logic of the diagnosing program is inspected and in which there is provided a function of inspecting a logic of a diagnosing program surely at a short period of time.